1) Crossroad : Sol, fiance to Prince Ni, is about to have a wedding ceremony. Suddenly, she said she wanted to go for a trip and the idea was denied. She couldn't give up on the idea and tried to run away from the castle...
Heart warming romantic love fantasy

2) Treasure

3) Mystery

4) Entrust!

Ore ni Kamauna is a story about two high school students who were child prodigy and genius. However, growing up as such talented individuals had led them to deal with a lot of pressures in life, thus, now their one goal in life is to make money...
(Source: Beautiful Soup)

High school student Makoto's life is turned upside down when Yusuke, Makoto's grandson from the future, appears before him asking for his help!

Sakuya and Wakyo are reincarnated and reunited only to discover that Bishu-sama — their master and mentor from a past existence — is in their midst and in grave danger from vengeful demons! Still unsure of their own powers and the nature of their cunning and elusive enemy, they must race against time to rescue Bishu from the dark forces that roil within his reincarnated form.
(Source: CMX)

Data is a kind of Magical Boy series manga by Tachibana Kaimu. The two main characters, Sakura and Yuki, are on quests to gather stones with magical powers. In doing so they are also hoping to uncover the mystery as to why they both seem to have lost their memory. Although this is a shoujo series, I'm pretty positive theres also something shounen-ai going on between the two (subtle but there....). A lot of new characters who are also "hosts" for the stones join in the fun as the story progresses. (Source: GOoC)